Several former neonatal intensive care unit patients greeted each other Sunday to celebrate the fact that, even though many of them were once only 1 pound at birth, they're now thriving.

The first few weeks of a premature baby's life tend to be a roller coaster of care and emotions, doctors said.

"They are long, hard nights. When things are tough, you wonder sometimes how you're going get through, but you come here and see how even the sickest child in the most dire circumstances turns out to do so very well," said Dr. Tuvia Blechman, the hospital's chief of neonatology.

Emily Mattingly is now 8 years old, but she was born premature at just 25 weeks. Emily spent the first 131 days of her life in the NICU.

"It's great to be able to come and celebrate and see the nurses and Dr. Blechman, who runs the NICU, and say thank you and let them see how Emily's grown. She was this big when she was born, and she's a lot bigger now," said her mother, Moira Mattingly.

The yearly reunion lets parents and staff, who were like family at one time, catch up.

"The nurses really become the aunts and the grandmas. They taught us how to change Emily's diaper. They taught us how to give her her first bath. All of these firsts that we had were really with the nurses and doctors in the NICU, so that's something you'll never forget," Mattingly said.

"We celebrate the successes that we and their families have had getting through a very difficult time," said Vick Broccolino, the hospital's president.